An air-pollution history of metallurgical innovation in iron- and steel- making: A geochemical archive of Sheffield

This paper explores file degree to which palaeoecological analyzes can determine the history of metallurgical innovation and complex technological developments that took place in the iron- and steel industries of the City of Sheffield, Yorkshire, England. A knowledge of the key scientific breakthroughs as well as documentary evidence of industrial growth and decline in Sheffield are used as base-line historical data with which to interpret the palaeoecological and geochemical evidence presented here as a result of investigations of peats and clays collected from the Tinsley Park Bog in the Lower Dim Valley of Sheffield. These deposits were analysed for charcoal, pollen, mineral magnetic properties and some trace elements (Ti, V, Fe, Co, Ni, Zn, and Pb). Metal concentrations (measured using AAS) were as high as 320 ppm Ni, 472 ppm Cu, 613 ppm Zn, and 827 ppm Pb. Compared to the typical concentrations found in crustal rocks, Ni is enriched in the peats and sediments by as much as a factor of 5 times, Cu and Zn by a factor of 10, and Pb by more than 60 times. The lowest concentrations of Cu, Ni, Zn and V were found in the basal peats of Tinsley Park Bog, arguing against a natural geochemical souse as the cause of the enrichments. The greatest Cu and Zn enrichments are found in the peats in the top 0.1 m of the bog, possibly an indication of a large Special Steels Plant which began production nearby in 1963. Below these levels in the peat, in contrast, Ni and V are relatively abundant. They are believed to reflect the manufacture of complex steels during the earlier part of the twentieth century. Lead is most abundant in samples from depths in the peat which are though to post-date the onset of coal utilisation at the nearby Rothervale Mine. Interpretation is hampered because at present there is no independent evidence of the antiquity of the peat deposits studied. Neither is there any clear understanding of the significance of the taphonomic processes which have influenced the geochemical and paleoecological records obtained from the deposits. Nevertheless, our present interpretation of the data presented here indicates that to a surprising extent, it is possible to detect in the peat monolith (i) evidence of the expansion and relative decline of the adjacent steel industry; (ii) the impact of this manufacturing economy and associated coal- mining upon the adjacent vegetation; and (iii) the introduction of trace elements in pure forms or as alloys, as steel-making processes developed through the 19th and 20th centuries.